Disruptive mood dysregulation disorder (DMDD) was added to DSM-5 to account for nonepisodic irritability and includes many of the criteria first proposed for severe mood dysregulation (the hyperarousal criterion was eliminated and the age of onset criterion was changed to 10 years old) (
1).
In a previous study of 3,258 participants from ages 2 to 17 years, DMDD was uncommon and frequently comorbid with other common childhood disorders, most frequently oppositional defiant disorder and depressive disorders. In fact, it was rare for DMDD to occur without comorbid disorder (an overlap of 63%−92%). Given their high levels of mood and behavioral dysregulation and also comorbidity, children with DMDD may be at elevated risk for long-term problems. We used the community-based, longitudinal Great Smoky Mountains Study to evaluate the adult psychiatric and functional outcomes of children with DMDD.
Several community and clinical studies have looked at long-term psychiatric outcomes of irritability (
2–
4). Brotman et al. (
2) followed children with severe mood dysregulation in late adolescence in a community longitudinal study. Children with severe mood dysregulation had a seven times greater risk of having a depressive disorder than children without severe mood dysregulation. A follow-up of chronically irritable children from another community longitudinal study found increased risk of major depression in early adulthood (
4). This same study looked at outcomes predicted after 20 years of follow-up and found that after adjustment for baseline comorbidities, childhood irritability predicted adult major depressive disorder, generalized anxiety, and dysthymia (
3). Together, these studies suggest that irritability is a key feature in risk for adult mood and possibly anxiety disorders. None of these long-term follow-up studies has, however, applied the new DSM-5 criteria for testing adult outcomes of childhood DMDD.
Psychiatric functioning is only one measure of long-term functioning. Individuals may or may not meet full criteria for an adult psychiatric disorder, but may still fail to attain optimal functioning in important life areas. The developmental literature on severe childhood irritability had previously reported that severely dysregulated children “move against” the world as they grow up—into a spiral of downward mobility, erratic work lives, and dysfunctional relationships (
5). Here, we tested whether meeting criteria for DMDD in childhood predicted adult health functioning, risky or illegal behaviors, or educational, financial, and social functioning. Taken together, our goal is to provide a broad psychiatric and functional outcomes profile of young adults with a history of DMDD.
The present analyses used the same sample followed by Brotman et al. (
2) in their late adolescent follow-up of children with severe mood dysregulation. We applied the DSM-5 DMDD criteria during childhood and adolescence, and looked at adult outcomes at ages 19, 21, and 24–26 years. In contrast to Brotman et al. (
2), we excluded the first wave of study from this analysis. We hypothesized that children with DMDD are a severe subset of childhood psychiatric cases and they display worse psychiatric and functional outcomes than noncases and some psychiatric comparison subjects. Previous research on severe mood dysregulation and chronic irritability suggest that adults with a history of DMDD may have the highest rates of anxiety and depression in particular.
Discussion
Irritability is a symptom or associated feature of many psychiatric disorders, but it is a core feature of DSM-5 DMDD. As such, DMDD is a distinct disorder in terms of its high rates of associated comorbidity (
9). Our study suggests that this pattern of comorbidity extends into adulthood, where case subjects who displayed rates of comorbidity five to seven times higher than rates observed for noncase and psychiatric comparison subjects were at increased risk for both anxiety and depressive disorders. The poor prognosis for individuals with DMDD also extended to health, legal, financial/educational, and social functioning. Indeed, the composite profile of DMDD case subjects in adulthood is one of pervasive, impaired functioning.
Children with DMDD were worse off in adulthood than children with other psychiatric disorders in a number of domains (depression, anxiety, psychiatric comorbidity, poverty, and low educational attainment). One possible explanation of this finding is that the severity of psychiatric symptoms is higher in children with DMDD relative to children with other common psychiatric disorders. It is also possible that this increased risk might be attributable to its high levels of comorbidity. These two interpretations are not exclusive. Indeed, in our sample, so few cases of DMDD were without a comorbid disorder that we could not test whether severity and comorbidity differentially contributed to adult outcomes. When we compared case subjects to psychiatric comparison subjects with multiple childhood disorders, DMDD case subjects had lower scores in all functional domains (i.e., worse functioning), but these differences were not statistically significant. We conclude that DMDD is a severe and highly comorbid childhood disorder that marks children at risk for long-term impaired functioning.
DMDD has proven to be controversial. Concerns include the potential for increased psychotropic medication use in children, pathologizing of “normal” tantrum behavior, and the lack of any empirical basis (
15–
18). This analysis and previous research (
9) suggests that the concern about pathologizing normal behavior is likely overstated: DMDD is relatively rare, almost always comorbid, and commonly associated with long-term impairment. These children should be a clinical priority. The risk of increased medication use (or psychotherapy) depends on what clinical trials suggest about the optimal treatment strategy and long-term outcomes of treatment for such children. Finally, the concerns about the lack of empirical basis are being addressed rapidly with basic epidemiological studies available before the publication of DSM-5 and also with extensive prior study of severe mood dysregulation and chronic irritability (
2–
4,
9,
19,
20).
One empirically supported critique of this new disorder is that DMDD is merely a new category for children with comorbid depression and oppositional defiant disorder (
9). The reason that DMDD can be studied in existing samples is that the criteria can be almost entirely derived from the symptomatic criteria for those two disorders (i.e., persistent irritable/angry affect punctuated by temper outbursts). Is it, therefore, necessary to propose a new category or is it sufficient to note this comorbidity group as one of interest? This distinction may be a reasonable taxonomic issue, but another validity criterion is how the diagnostic entity informs prognosis and treatment planning. Our findings suggest that this disorder identifies children who in some cases may have a worse prognosis than children with other common psychiatric disorders.
It is important to note several potential limitations. The Great Smoky Mountains Study is not nationally representative; compared with the U.S. population, the study overrepresents American Indians and underrepresents blacks. Rates of poverty in children who have participated in the Great Smoky Mountains Study are slightly higher than are found in the United States in similar age cohorts. Despite these caveats, prevalence rates for common disorders and comorbidity patterns derived from these studies are similar to those from other community epidemiologic studies (
21–
23). To date, there is no nationally representative longitudinal study of childhood mental health that has used gold standard psychiatric interviews. Thus, geographically limited, epidemiologic, longitudinal studies like this one have been an important source of information on the etiology, phenomenology, and developmental course of childhood psychopathology.
The study attempted to minimize recall biases and forgetting by focusing interviews on the 3 months immediately preceding the interview. At the same time, individuals may have met criteria for DMDD outside of our assessment window. To the extent that cases were not identified, our results underestimate the long-term effect of DMDD. Finally, diagnostic criteria were applied post hoc using symptoms of oppositional defiant disorder and depressive disorders, as the diagnosis had not been proposed at the time of the interviews. As such, additional information about this particular constellation of symptoms, apart from oppositional defiant disorder and depressive disorders (e.g., impairments and service use) was not collected.
Conclusions
Disruptive mood dysregulation disorder is a new disorder to DSM-5, and there is no question that research on irritability has increased dramatically over the last decade, but children with this constellation of symptoms have always been with us (
24). Caspi et al. (
5) described children with high levels of temper tantrums as “moving against the world” and documented their downward social mobility and turbulent social lives. Our analysis suggests that this bleak prognosis includes increased health problems, continued emotional distress, financial strain, and social isolation. For most children, development provides a constant series of opportunities for recovery and rehabilitation (
25), but for children with DMDD, the accumulation of early failures may perpetuate a lifetime of limited opportunity and compromised well-being. As such, children with persistent irritable mood punctuated by frequent outbursts—regardless of what we call this cluster of symptoms—should be a priority for clinical care and treatment development.